> For the complete documentation index, see [llms.txt](https://dbpedia.gitbook.io/databus/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dbpedia.gitbook.io/databus/download-client/usage.md).

# Usage

The client has many parameters, which describe what data needs to be downloaded, and how it needs to be converted. There are many ways to use the client, which are described in the following chapters.

## Databus Client Parameters

<table><thead><tr><th width="322.3333333333333">Option</th><th>Description</th><th>Default</th></tr></thead><tbody><tr><td>-s, --source</td><td>Set the source you want to convert. A source can either be a <code>[file/directory]</code> to convert already existing files, or a <code>[query file/query string/collection URI]</code> to convert queried files. Notice that query files must have <code>.sparql</code>/<code>.query</code> as extension to be recognized.</td><td></td></tr><tr><td>-e, --endpoint</td><td>Set the sparql endpoint, where the query should be fired to. If you use a collection you don't need this parameter, because its detected automatically. Otherwise its mandatory.</td><td></td></tr><tr><td>-t, --target</td><td>Set the target directory for converted files</td><td><code>./files/</code></td></tr><tr><td>-c, --compression</td><td>Set the compression format of the output file</td><td><code>same</code></td></tr><tr><td>-f, --format</td><td>Set the file format of the output file</td><td><code>same</code></td></tr><tr><td>-m, --mapping</td><td>Set the mapping file for format-conversion to different format equivalence class</td><td></td></tr><tr><td>-d, --delimiter</td><td>Set the delimiter (only necessary for some formats)</td><td>,</td></tr><tr><td>-q, --quotation</td><td>Set the quotation (only necessary for some formats)</td><td>"</td></tr><tr><td>--createMapping</td><td>Do you want to create mapping files for mapped sources?</td><td>false</td></tr><tr><td>-g, --graphURI</td><td>Set the graph uri for mapping from rdf triples to rdf quads</td><td></td></tr><tr><td>-b, --baseURI</td><td>set the base URI to resolve relative URIs</td><td></td></tr><tr><td>-o, --overwrite</td><td>true -> overwrite files in cache, false -> use cache</td><td><code>true</code></td></tr><tr><td>--clear</td><td>true -> clear Cache</td><td><code>false</code></td></tr><tr><td>--help</td><td>Show this message</td><td></td></tr></tbody></table>

## Queries

Various datasets are registered on the DBpedia Databus in the form of files. A query specifies an exact selection of these records of the [DBpedia Databus](https://databus.dbpedia.org/) to be processed by the Databus Client. Therefore, the query is one of, if not the most important parameter of the client.

### Possible queries

You can pass any query that selects the object of the predicate `databus:file`, the name of the variable does not matter. The query should look like.\
`SELECT ?o WHERE { ?s databus:file ?o}`

### How to pass queries

There are three different ways to pass a query to the Databus Client:

1. Pass the query string directly as a parameter.
   * **Note:** this option does not work for [CLI](/databus/download-client/usage/cli.md)
2. Save the query in a file and pass the file path as a parameter.
   * The file extension of the query file must be `.sparql` or `.query`.
3. Collection URIs are also supported. The client receives the associated query itself.
   * e.g. <https://dev.databus.dbpedia.org/testuser/collections/testcollection/>